Providing HVAC services in Boulder, CO and surrounding areas since 1994, we at Welzig Heating and Air have found that the average home suffers significant energy losses due to duct leaks. Our duct sealing services help local homeowners optimize the efficiency of their heating and cooling systems. The benefits go beyond reducing utility costs and carbon footprint, working to improve comfort, air quality, and reliability of equipment.

Duct Sealing for Efficient HVAC

Welzig Heating and Air looks forward to sharing this worthwhile home improvement strategy with you. Our sealing process causes no damage or disruption, is completed quickly, and ensures that the conditioned air produced by the HVAC system reaches the intended living spaces. Both the supply and return sides of the ducts are susceptible to air loss. With testing and inspection, we pinpoint concerns, offer honest recommendations and complete all aspects of the job to exacting standards of job performance.

Make Sure Your Ducts are Sealed

According to the US EPA, the average household wastes approximately 20 to 30% of conditioned air through duct leaks. Don’t take chances with the enjoyment, health, and budget of your home. Take advantage of satisfaction guaranteed from Welzig Heating and Air, anywhere across Boulder, Longmont, Louisville, and Lafayette, CO. Our experience, expertise, and in-house sheet metal fabrication shop prepare us for the toughest challenges.

Duct Sealing Service, Sealing Ducts & Ductwork Sealing Boulder, CO, Longmont, CO, Louisville, CO & Lafayette, CO

Ductwork Sealing in Boulder, CO | Sealing Ducts Longmont, CO | Duct Sealing Service Louisville, CO

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Satisfied Customers
They Speak For Us

Dave Kaplan-Gomez and James Miltersen installed my new Tankless Water Heater. Both were polite and professional. Care was taken not to damage anything in my house which I really appreciated. I use Welzig for all my HVAC needs and highly recommend them.


Our 23-year-old A/C system ran out of “borrowed time” and became too difficult to continue maintaining. With great advice from Casey Welzig,, we replaced the old system with a Bryant Evolution A/C system. Max Loustaunau and Seth Bernhardt did an excellent job with removing the old system and installing the new one. Both of them are great to work with — very professional and very personable. We are really amazed at how much better the new system works!


Bob came out to look at our swamp cooler and was remarkably helpful and professional. Not only did he give me a knowledgeable diagnosis, but he also taught me a lot in the process. We’ll be calling him for all future needs with our cooling system.

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